1 files changed, 44 insertions, 35 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfException.cpp b/lib/CodeGen/AsmPrinter/DwarfException.cpp
index c6c59f5..2b08ba4 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfException.cpp
@@ -638,18 +638,18 @@ void DwarfException::EmitExceptionTable() {
   const unsigned LandingPadSize = SizeOfEncodedValue(dwarf::DW_EH_PE_udata4);
   bool IsSJLJ = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
   bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
-  unsigned SizeSites;
+  unsigned CallSiteTableLength;
 
   if (IsSJLJ)
-    SizeSites = 0;
+    CallSiteTableLength = 0;
   else
-    SizeSites = CallSites.size() *
+    CallSiteTableLength = CallSites.size() *
       (SiteStartSize + SiteLengthSize + LandingPadSize);
 
   for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
-    SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
+    CallSiteTableLength += MCAsmInfo::getULEB128Size(CallSites[i].Action);
     if (IsSJLJ)
-      SizeSites += MCAsmInfo::getULEB128Size(i);
+      CallSiteTableLength += MCAsmInfo::getULEB128Size(i);
   }
 
   // Type infos.
@@ -698,7 +698,20 @@ void DwarfException::EmitExceptionTable() {
   Asm->OutStreamer.SwitchSection(LSDASection);
   Asm->EmitAlignment(2, 0, 0, false);
 
+  // Emit the LSDA.
   O << "GCC_except_table" << SubprogramCount << ":\n";
+  EmitLabel("exception", SubprogramCount);
+
+  if (IsSJLJ) {
+    SmallString<16> LSDAName;
+    raw_svector_ostream(LSDAName) << MAI->getPrivateGlobalPrefix() <<
+      "_LSDA_" << Asm->getFunctionNumber();
+    O << LSDAName.str() << ":\n";
+  }
+
+  // Emit the LSDA header.
+  EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
+  EmitEncodingByte(TTypeEncoding, "@TType");
 
   // The type infos need to be aligned. GCC does this by inserting padding just
   // before the type infos. However, this changes the size of the exception
@@ -707,7 +720,7 @@ void DwarfException::EmitExceptionTable() {
   // So by increasing the size by inserting padding, you may increase the number
   // of bytes used for writing the size. If it increases, say by one byte, then
   // you now need to output one less byte of padding to get the type infos
-  // aligned.  However this decreases the size of the exception table. This
+  // aligned. However this decreases the size of the exception table. This
   // changes the value you have to output for the exception table size. Due to
   // the variable length encoding, the number of bytes used for writing the
   // length may decrease. If so, you then have to increase the amount of
@@ -716,41 +729,35 @@ void DwarfException::EmitExceptionTable() {
   // We chose another solution: don't output padding inside the table like GCC
   // does, instead output it before the table.
   unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
-  unsigned TyOffset = sizeof(int8_t) +          // Call site format
-    MCAsmInfo::getULEB128Size(SizeSites) +      // Call site table length
-    SizeSites + SizeActions + SizeTypes;
-  unsigned TotalSize = sizeof(int8_t) +         // LPStart format
-                       sizeof(int8_t) +         // TType format
-    (HaveTTData ?
-     MCAsmInfo::getULEB128Size(TyOffset) : 0) + // TType base offset
-    TyOffset;
+  unsigned CallSiteTableLengthSize =
+    MCAsmInfo::getULEB128Size(CallSiteTableLength);
+  unsigned TTypeBaseOffset =
+    sizeof(int8_t) +                            // Call site format
+    CallSiteTableLengthSize +                   // Call site table length size
+    CallSiteTableLength +                       // Call site table length
+    SizeActions +                               // Actions size
+    SizeTypes;
+  unsigned TTypeBaseOffsetSize = MCAsmInfo::getULEB128Size(TTypeBaseOffset);
+  unsigned TotalSize =
+    sizeof(int8_t) +                            // LPStart format
+    sizeof(int8_t) +                            // TType format
+    (HaveTTData ? TTypeBaseOffsetSize : 0) +    // TType base offset size
+    TTypeBaseOffset;                            // TType base offset
   unsigned SizeAlign = (4 - TotalSize) & 3;
 
-  for (unsigned i = 0; i != SizeAlign; ++i) {
-    Asm->EmitInt8(0);
-    EOL("Padding");
-  }
-
-  EmitLabel("exception", SubprogramCount);
-
-  if (IsSJLJ) {
-    SmallString<16> LSDAName;
-    raw_svector_ostream(LSDAName) << MAI->getPrivateGlobalPrefix() <<
-      "_LSDA_" << Asm->getFunctionNumber();
-    O << LSDAName.str() << ":\n";
+  if (HaveTTData) {
+    // Account for any extra padding that will be added to the call site table
+    // length.
+    EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
+    SizeAlign = 0;
   }
 
-  // Emit the header.
-  EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
-  EmitEncodingByte(TTypeEncoding, "@TType");
-
-  if (HaveTTData)
-    EmitULEB128(TyOffset, "@TType base offset");
-
   // SjLj Exception handling
   if (IsSJLJ) {
     EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
-    EmitULEB128(SizeSites, "Call site table length");
+
+    // Add extra padding if it wasn't added to the TType base offset.
+    EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
 
     // Emit the landing pad site information.
     unsigned idx = 0;
@@ -791,7 +798,9 @@ void DwarfException::EmitExceptionTable() {
 
     // Emit the landing pad call site table.
     EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
-    EmitULEB128(SizeSites, "Call site table length");
+
+    // Add extra padding if it wasn't added to the TType base offset.
+    EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
 
     for (SmallVectorImpl<CallSiteEntry>::const_iterator
          I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {